instruction_seed stringlengths 292 48.7k | found_ngrams listlengths 0 21 |
|---|---|
Apparently yes! In three easy steps.
Step 1
Let f(n) denote the prime-counting function (number of primes less than or equal to n).
Define the integer sequence s(n) as follows. For each positive integer n,
Initiallize t to n.
As long as t is neither prime nor 1, replace t by f(t) and iterate.
The number of iterations ... | [] |
As computer scientists, you're probably all familiar with the basic list operations of pop and push. These are simple operations that modify a list of elements. However, have you ever heard of the operation flop? (as in flip-flop)? It's pretty simple. Given a number n, reverse the first n elements of the list. Here's a... | [
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[
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] |
Your task is to model the effects of batter on pieces of food. Please add three layers of crust.
[[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0], // in
[0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,1,1,1,0,0,0,0,0,0,0,1,1,0,0,0],
[0,0,0,0,1,0,0,0,0,0,0,0,1,1,0,1,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,0],
[0,0,0,0,0,0,0,0... | [] |
Task
Given a list of integers L and another integer s, the goal is to compute the column-wise sums of all s-length (potentially overlapping) slices of L, while pertaining their positions relative to L (see below).
Definitions
The s-length (overlapping) slices of the list L are all the contiguous subsequences (without w... | [
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The brethren from the order of St Golfus the Concise have a tradition of reciting a short prayer whenever they see someone make the sign of the cross. Due to the high level of sin measured among tourists recently, they have installed CCTV in the monastery, and they've hired you to help them keep old tradition alive in ... | [] |
There are n places set around a circular table. Alice is sat on one of them. At each place, there's a cake. Alice eats her cake, but it doesn't taste very nice. Then the Mad Hatter comes in. He gives Alice a list of n-1 numbers, each between 1 and n-1. For each item i in the list, Alice has to move around i places and ... | [] |
You are given an array A of n strictly positive integers, with n ≥ 2.
Your task is to map each entry Ai to:
1 if Aj mod Ai is odd for each j such that 1 ≤ j ≤ n and j ≠ i
2 if Aj mod Ai is even for each j such that 1 ≤ j ≤ n and j ≠ i
0 otherwise (mixed parities)
Example
For A = [ 73, 50, 61 ], we have:
50 mod 73 = ... | [] |
Most everyone here is familiar with Pascal's Triangle. It's formed by successive rows, where each element is the sum of its two upper-left and upper-right neighbors. Here are the first 5 rows (borrowed from Generate Pascal's triangle):
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
. . .
Collapse these rows to the left
1
1... | [] |
You will be given a square matrix of integers M and another positive integer n, strictly smaller than the size of M. Your task is to generate all square sub-matrices of M of size n.
For the purposes of this challenge, a square sub-matrix is a group of adjacent rows and columns contained in M.
Input / Output Formats
Yo... | [] |
Local periods
Take a non-empty string s.
The local period of s at index i is the smallest positive integer n such that for each 0 ≤ k < n, we have s[i+k] = s[i-n+k] whenever both sides are defined.
Alternatively, it is the minimal length of a nonempty string w such that if the concatenation w w is placed next to s so t... | [] |
The Challenge
Given a number, find the sum of the non-composite numbers in the Fibonacci sequence up to that number, and find the prime factors of the sum.
For example, if you were given 8, the non-composite numbers would be 1, 1, 2, 3, and 5. Adding these up would get 12. The prime factors of 12 are 2, 2 and 3, so you... | [] |
Introduction
Your task is to generate the first 1000 terms in the continued fraction representation of digit-wise sum of square root of 2 and square root of 3.
In other words, produce exactly the following list (but the output format is flexible)
[2, 6, 1, 5, 7, 2, 4, 4, 1, 11, 68, 17, 1, 19, 5, 6, 1, 5, 3, 2, 1, 2, 3,... | [
[
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18,
11,
220
],
[
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16,
11,
220,
16,
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220,
18,
11,
220,
21,
11
],
[
220,
16,
11,
220,
16,
11,
220,
18,
11,
22... |
I was at a friend's house for dinner and they suggested the idea of a "Prime-factor vector space". In this space the positive integers are expressed as a vector such that the nth element in the vector is the number of times the nth prime divides the number. (Note that this means that our vectors have an infinite numb... | [] |
A Brainfuck derivative
Let's define a simple Brainfuck-like programming language.
It has a two-directional tape of cells, and each cell holds one bit.
All bits are initially 0.
There is a moving head on the tape, initially at position 0.
A program is a string over the characters <>01!, executed from left to right, with... | [] |
Grouping takes a list and splits it into new lists of equal adjacent elements. For example
[1,1,2,1,1] -> [[1,1],[2],[1,1]]
If you then take the length of these groups you get a new list of integers
[1,1,2,1,1] -> [2,1,2]
Your task is to write a program that takes a list of positive integers and find the number of t... | [] |
This challenge is inspired by this, now deleted question.
Take a positive integer N as input, and output a matrix with the numbers 1 .. N2 that follows the pattern below:
Fill in the first row with 1 .. N then fill the last row (row number N) with (N+1) .. 2N, then fill the second row with (2N+1) .. 3N and continue un... | [] |
Challenge:
Input:
An integer n (> 0)
An integer-array a of size > 0 (which contains positive and negative values, but no zeroes)
Output:
First output the first n items
Then take the last item you've outputted (let's call it e), and go e steps forward if e is positive, or abs(e) steps backwards if e is negative. And ... | [
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20,
11
],
[
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18,
11,
220... |
The challenge is to write the fastest code possible for computing the Hafnian of a matrix.
The Hafnian of a symmetric 2n-by-2n matrix A is defined as:
$$\operatorname{haf}(A)=\frac{1}{n ! 2^n} \sum_{\sigma \in S_{2 n}} \prod_{j=1}^n A_{\sigma(2 j-1), \sigma(2 j)}$$
Here \$ S_{2 n} \$ represents the set of all permutati... | [] |
Block shuffle sort
The block shuffle sort is a (rather artificial) method of sorting a list.
It works as follows, illustrated by an example.
[6, 1, 0, 3, 2, 4, -2, -1]
Break list into contiguous blocks
[6][1, 0][3, 2, 4][-2, -1]
Sort each block
[6][0, 1][2, 3, 4][... | [
[
220,
16,
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18,
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We have many challenges based on base 10, base 2, base 36, or even base -10, but what about all the other rational bases?
Task
Given an integer in base 10 and a rational base, return the integer in that base (as an array, string, etc.).
Process
It's difficult to imagine a rational base, so let's visualize it using Expl... | [] |
This is a repost of an old challenge, in order to adjust the I/O requirements to our recent standards. This is done in an effort to allow more languages to participate in a challenge about this popular sequence. See this meta post for a discussion of the repost.
The Kolakoski sequence is a fun self-referential sequen... | [] |
A maze is given as a matrix of 0s (walls) and 1s (walkable space) in any convenient format. Each cell is considered connected to its 4 (or fewer) orthogonal neighbours. A connected component is a set of walkable cells all transitively connected to each other. Your task is to identify the cutpoints - walkable cells whic... | [] |
Given a triangulation of the surface of a polyhedron p, calculate its Euler-Poincaré-Characteristic χ(p) = V-E+F, where V is the number of vertices, E the number of edges and F the number of faces.
Details
The vertices are enumerated as 1,2,...,V. The triangulation is given as a list, where each entry is a list of the ... | [] |
The Challenge
Your program should take 3 inputs:
A positive integer which is the number of variables,
A set of unordered pairs of nonnegative integers, where each pair represents an equality between variables, and
A positive integer which represents the starting variable,
It should return a set of nonnegative integer... | [
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],
[
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20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
Four integer sequences
In this challenge, you will test four different properties of a positive integer, given by the following sequences.
A positive integer N is
perfect (OEIS A000396), if the sum of proper divisors of N equals N. The sequence begins with 6, 28, 496, 8128, 33550336, 8589869056, 137438691328, 23058430... | [] |
The input is an array (or space-separated string, as you wish), zero-indexed, consisting of one strictly increasing array and one strictly decreasing array (in this order, not other vice versa), each having a length of 2 at least. Example is:
-10 -2 4 18 38 46 28 19 10
The goal is to write the fastest algorithm to fin... | [] |
The rules are as follows:
Take in a string of integers separated by spaces. Add the first and last numbers, the second and second-last numbers, and so on.
The program must output the numbers separated by newlines.
The program must handle negative numbers, but may not handle decimals.
If an odd amount of integers are i... | [] |
Alice (A) and Bob (B) decided to have a battle.
Each combatant has 10 health.
They take turns to roll a 6 sided die for damage.
That damage is removed from their opponent's health.
In the end either Alice or Bob, will vanquish their foe.
Show me how the battle went. Outputting these codes for the actions which have ... | [
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],
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220,
20,
11
],
[
220,
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220,
17,
11,
220,
18,
11,
220... |
Self-limiting lists
Consider a nonempty list L containing nonnegative integers.
A run in L is a contiguous sublist of equal elements, which cannot be made longer.
For example, the runs of [0,0,1,1,3,3,3,2,1,1] are [0,0], [1,1], [3,3,3], [2], [1,1].
The list L is self-limiting if for each integer N ≥ 1, the number of oc... | [] |
This challenge already describes dropsort. However, I'm kinda lazy and I really only need my array to be a bit more sorted than before, it doesn't need to be sorted all the way.
In Drop Sort, we drop every element less than any element before it. In Lazy Drop Sort, we drop every element less than the one strictly prece... | [] |
Inspired by this.
Agatha Stephendale, a sophomore who is really into raster graphics, has taken a course in linear algebra. Now she imagines matrices as rectangles, but in her artistic mind, she attaches diagonal lines to those rectangles and tries to compute traces along them. In fact, she wants to compute traces of a... | [] |
Overview
Given the integer representation of three elements in GF(2^64), give the product of the first two elements over GF(2^64) with the reducing polynomial defined as the polynomial m such that m(x) = x^64 + n(x), where n is the polynomial representation of the third element.
You want me to what?
A finite field GF(... | [] |
Your task is to accept as input two gene sequences, and a sequence of "cross over points", and return the gene sequence that results from the indicated cross overs.
What I mean by this is, say you have the sequences [A, A, A, A, A, A, A] and [Z, Z, Z, Z, Z, Z, Z], and cross over points of 2 and 5. The resulting sequenc... | [] |
In this simple challenge you are given an input array L of non-negative integers and a number of bins b greater than 0 but no more than the length of L. Your code must return a new array M whose length is b and which has binned the array L. This is easiest explained with examples.
L = [1,0,5,1] and b = 2 returns M = [1... | [] |
Introduction
For as long as programmers have been programming and as long as English teachers have been teaching, there's a controversy over the datasets called Arrays and Lists (or hashes).
Arrays have almost always had their first index at 0. Which, for the programmer, is understandable because of math. But along the... | [
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]
] |
Background
IEEE 754 Double-precision floating-point format is a way to represent real numbers with 64 bits. It looks like the following:
A real number n is converted to a double in the following manner:
The sign bit s is 0 if the number is positive, 1 otherwise.
The absolute value of n is represented in the form 2**y... | [] |
Input:
A 2D array containing two distinct (optional) values.
I'll use 0 and 1 when explaining the rules. The input format is of course flexible.
Challenge:
Zeros are water, and ones are islands. In order to ensure loneliness, your task is to surround all islands with water by inserting rows and columns of zeros. You d... | [] |
Description :
Given a string of space separated binary digits or space separated booleans or an array of binary digits or array of booleans . Your job is to find the xor of each until you end up with one answer either 0 or 1. The inputs will always be valid and will only be either 0 or 1.
Example :
1 0 0 1 0 --> 0
1 0 ... | [] |
You're given the map of a cinema theatre as a boolean matrix: 0 represents a free seat, 1 - occupied. Each Finn who walks in chooses the seat farthest away (Euclidean distance) from the nearest occupied one, or if several such exist - the first among them in row-major order. Output a matrix showing the order seats will... | [] |
For a computer language, a reserved word is a word that cannot be used as an identifier, such as the name of a variable, function, or label. For other computer languages, keywords can be considered as the set of the language instructions.
Challenge
Using your language of choice, write a code in the chosen language that... | [
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20,
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],
[
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17,
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18,
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Recursively define a "valid arithmetic expression":
Any natural number is a valid arithmetic expression.
If s is a valid arithmetic expression, then so is (-s).
If p and q are valid arithmetic expressions, then so is (p+q).
In the above, a "natural number" is recursively defined as follows:
0 1 2 3 4 5 6 7 8 9 are n... | [] |
Back in the day, telephone autodialers used punched cards with one column for each digit of the number to be dialed. Columns had seven rows. The first three rows represented the numbers (1,2,3), (4,5,6), and (7,8,9) respectively. The last three rows rotated this arrangement by 90°: (1,4,7), (2,5,8), and (3,6,9). The mi... | [] |
Interleaved sequences represent an arbitrary merging of some number of sequences.
An interleaved sequence can be made by appending elements to a list one by one from some number of lists, choosing the next element from some list each time. Therefore, an interleaved sequence will contain exactly the same elements of all... | [
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18,
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19,
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20,
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],
[
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17,
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18,
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Take the numbers 0, 1, 2, 3, 4, ... and arrange them in a clockwise spiral, starting downward, writing each digit in its own separate square.
Then, given one of four distinct and consistent ASCII characters (your choice) representing an axis, and an input integer n, output the first n terms of the sequence described by... | [
[
220,
16,
11,
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16,
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220,
17,
11,
220,
18,
11,
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]
] |
Write the shortest program or function which generates these 1000 numbers or a sequence (0- or 1-indexed) which begins with them.
[0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0,
1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1,
0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1,... | [] |
I've been recently playing through 'The Weaver' and I think it presents an interesting challenge for code-golf.
Premise:
The Weaver is a game wherein you are given a number of ribbons coming from 2 directions 90 degrees apart and your goal is to swap them at certain intersections to achieve a desired output.
Like th... | [] |
Today was AP exam registration day at my school, and while I was meticulously bubbling in the pages and pages of information required, the idea for this challenge hit me. So, given a string of letters and numbers, output an appropriately filled out bubble chart.
Rules:
For each character in the input string, replace t... | [] |
The input consists of i rows with neighbors information. Each ith row contains 4 values, representing the neighbor of i to the North, East, South and West directions, respectively. So each value represents a neighbor at the given direction of the ith row, starting from row 1, and can go up to 65,535 rows. The 0 value i... | [] |
This question is similar to Biggest Square in a grid.
Challenge
Given a matrix of 1 and 0 in a string format "xxxx,xxxxx,xxxx,xx.." or array format ["xxxx","xxxx","xxxx",...], You will create a function that determines the area of the largest square submatrix that contains all 1.
A square submatrix is one of equal widt... | [] |
Find the area of a region of unit cells given its perimeter loop as a sequence of 90-degree turns.
For example, take the three-cell region
XX
X
whose perimeter loop we draw
L<S<L
v ^
S R>L
v ^
L>L
Each turn is marked as left (L), straight (S), or right (R). Starting from the R, the turns are RLLSLSLL. So, given in... | [] |
Let's say that this array is how many press-ups I've achieved each day in the last 28 days:
[
20,20,20,30,30,30,30,
35,35,40,40,40,45,45,
50,50,50,50,50,50,50,
60,70,80,90,100,110,120
]
As you can see, it's taken a steep upward trend in the last week, and that's the part of this data I'm most interested in. Th... | [] |
This was inspired by a math problem I saw somewhere on the internet but do not remember where (UPDATE: The original problem was found on the math riddles subreddit with a proof provided that it is possible, also see this Math SE post), asking for a proof if the following process is possible for any arbitrary pair of in... | [] |
Let an 8x8 chessboard be represented by any two distinct values, with one value being an empty square and the other being a queen. In the following examples, I use 0s as the empty squares and 1s as queens. For example:
is given by
1 0 1 1 1 0 0 0
1 0 1 0 1 0 1 1
1 0 1 0 1 1 0 1
0 1 0 1 0 1 0 0
0 1 1 0 0 1 0 1
1 0 0 0 ... | [] |
Mölkky
Mölkky is a Finnish throwing game. The players use a wooden pin (also called "mölkky") to try to knock over wooden pins of almost similar dimensions with the throwing pin, marked with numbers from 1 to 12. The initial position of the pins is as follows:
(07)(09)(08)
(05)(11)(12)(06)
(03)(10)(04)
(01)... | [] |
Challenge
Let's imagine an N-tuple of integers between 0 and M inclusive, and let's call it F.
There are (M + 1) ** N possible Fs in total.
How many such Fs satisfy all of the following inequalities (index is one-based)?
F[n] + F[n+1] <= M for 1 <= n < N
F[N] + F[1] <= M
Write a program or function that takes two pos... | [] |
Imagine an arsonist walking around the town and picking its victims according to a very specific pattern (Or, alternatively, Imagine a bee flying around the garden and picking its flowers to pollenize according to a very specific pattern). Let's say the town is an N × N matrix, where N is an integer higher than or equa... | [] |
The 21 Hairstyles of the Apocalypse
Given a a list of numbers between 1 and 21 (or 0 and 20) output a "stitched together" drawing of the following faces (see rules for stitching information):
___ ,,, ooo === +++ ### -*~*-
(o o) (o o) ... | [] |
Given a nonempty list of positive integers \$(x, y, z, \dots)\$, your job is to determine the number of unique values of \$\pm x \pm y \pm z \pm \dots\$
For example, consider the list \$(1, 2, 2)\$. There are eight possible ways to create sums:
\$+ 1 + 2 + 2 \to +5\$
\$+ 1 + 2 − 2 \to +1\$
\$+ 1 − 2 + 2 \to +1\$
\$+ 1... | [
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Input: An array I of k positive integers. The integers will be no larger than 100 and k ≤ 100.
Output: Your code must output all possible arrays O of non-negative integers of length k with the restriction that 0 ≤ Oi ≤ Ii. To get from one array to the next you may add or subtract 1 to one value in the array. Your co... | [] |
Given this list of all the words in english and a string with s_me missi_g lett__s, find one way to fill in the letters. Do note that some words on the list contain special characters (! & ' , - . /) and numbers
Input:
This list and a string with missing letters.
The input sentence can contain or be missing any of thes... | [] |
Challenge
Given an integer n ≥ 4, output a permutation of the integers [0, n-1] with the property that no two consecutive integers are next to each other. The value of a permutation pi is the sum of abs(pi[i] - i) for all indices i.
Examples
(1, 3, 0, 2) has value 6
(0, 2, 4, 1, 3) has value 6
(0, 2, 4, 1, 3, 5) ha... | [] |
You are probably familiar with the Fibonacci sequence where the first two terms are 0, 1 (or sometimes 1, 1) and every term after that is the sum of the previous two. It starts like this:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
Sometimes, the sequence contains numbers that have a particular pattern that I find int... | [
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220,
16,
11,
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16,
11,
220,
17,
11,
220,
18,
11,
220
],
[
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16,
11,
220,
17,
11,
220,
18,
11,
220,
20
],
[
11,
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16,
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17,
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18,
11... |
Consider the infinite matrix:
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 0 2 3 0 0 2 3 0 0 2 3 0 0 2 3
0 0 0 4 5 6 0 0 0 4 5 6 0 0 0 4 ...
0 0 0 0 7 8 9 10 0 0 0 0 7 8 9 10
0 0 0 0 0 11 12 13 14 15 0 0 0 0 0 11
...
Each new row of the matrix is co... | [] |
Challenge
Given a matrix of positive integers, determine if there are any "rings" of mountains. The formal definition for this challenge is: given a matrix of positive integers, is there any positive integer n for which there is a closed ring of cells in the matrix that are strictly greater than n such that all cells e... | [] |
Consider a one-dimensional sequence of numbers within a fixed range, i.e.
[1, 2, 4, 6, 8, 0, 2, 7, 3] in range [0, 10⟩
The Ever-Increasing Graph* ** is a line that connects all the points in this sequence left to right, and always goes upwards or stays level. If necessary, the line wraps around from top to bottom and ... | [
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Your task is to write a program or a function that outputs n random numbers from interval [0,1] with fixed sum s.
Input
n, n≥1, number of random numbers to generate
s, s>=0, s<=n, sum of numbers to be generated
Output
A random n-tuple of floating point numbers with all elements from the interval [0,1] and sum of all el... | [] |
Given an integer matrix a and a nonnegative integer i, output a mapping b that maps the distinct values in the ith column of a to rows of a who have that value in the ith column.
You may assume that i is in the half-open range [0, num_cols(a)) (or [1, num_cols(a)] if you choose to use 1-based indices), and that all int... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
]
] |
We all know that a lot of exercises only affect one half of your body, so you have to do them twice, once for each side. Such exercises have two counterparts, one for the left side and one for the right. However, there's no need to execute the two counterparts consecutively, as long as the exercises for both sides are ... | [] |
The task is taken from an MIT lecture by Prof. Devadas called You can read minds. A detailed explanation of the trick can be found in the linked video, or in this document. I'll try to explain it in simpler terms.
It turns out this was invented in the 1930's, and is known as the "Five-Card Trick of Fitch Cheney".
The ... | [] |
There's a type of n×n matrix W called the basic Weyr canonical form. Such a matrix is described by its blocks and has the following properties, using the following reference diagram:
the main diagonal blocks Wii are ni×ni matrices of the form λIni where Ini is the ni×ni identity matrix.
n1 ≥ n2 ≥ ... ≥ nr
the first s... | [] |
Definitions
The kth ring of a square matrix of size N, where 1 ≤ k ≤ ceiling(N/2) is the list formed by the elements of the kth and (N-k+1)th rows and columns, but without the first and last k-1 elements.
Example:
Matrix:
1 2 3 4 5
6 7 8 9 1
8 7 6 5 4
3 2 1 9 8
7 6 5 4 3
Delimited in rings:
+-------------------+
| ... | [] |
Given an array of numbers with length >=3 and length % 3 == 0
[1, 2, 3, 4, ...]
You will split it in sub-arrays of length 3
[[1, 2, 3], [4, 5, ...], [...
And return an array with
[0] => The amount of cases in the sub-array where all numbers are equal
[1] => In case all numbers in sub-array are not equal, the amount ... | [] |
Challenge
Given a sequence of numbers, create a function which returns the sequence steps.
Assume a sequence will be N >= 3
Sequence will repeat it steps at least once
Sequence will only contain natural numbers
Your function or program should return the shortest possible sequence of steps
Example:
Input: [1, 2, 3, 5,... | [] |
Inspiration.
Consider a list l, consisting of numbers. Define a block operation at index i on the list l to be the act of moving 3 consecutive elements starting from i in l to the end.
Example:
l, i (1-indexing) -> l (after applying block operation at index i)
[1,2,3,4,5], 1 -> [4,5,1,2,3]
[1,2,3,4,5,6,7], 3 -> [1,2,6,... | [] |
Background
Nonogram, also known as Picross or Griddlers, is a puzzle where the objective is to determine if each cell on the 2D grid should be colored or left blank, using the numbers of consecutive colored cells on each line.
The following is an example Nonogram puzzle with solution.
The problem is, some commercial N... | [] |
This challenge is really simple (and a precursor to a more difficult one!).
Given an array of resource accesses (simply denoted by nonnegative integers) and a parameter n, return the number of cache misses it would have assuming our cache has capacity n and uses a first-in-first-out (FIFO) ejection scheme when it is fu... | [
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220
]
] |
Introduction
In a private chat, a friend of mine apparently recently stumbled across a security system which has the following two restrictions on its valid pins:
Each digit must be unique (that is "1" may only appear once)
The order of the digits doesn't matter ("1234"="4321")
So to illustrate how bad this padlock s... | [] |
Problem Description
Given:
a function \$f(a, b, c, d, e) = \frac{a \times b}c + \frac de\$
an array \$x = [x_1, x_2, x_3, x_4, ..., x_n]\$ of non-distinct integers
a target value \$k\$
What is the most efficient way, in terms of worst-case \$n\$, to find 5 distinct indices \$x_a, x_b, x_c, x_d, x_e\$ from \$x\$ such ... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
First, let's talk about Beatty sequences. Given a positive irrational number r, we can construct an infinite sequence by multiplying the positive integers to r in order and taking the floor of each resulting calculation. For example,
If r > 1, we have a special condition. We can form another irrational number s as s =... | [
[
16,
11,
220,
16,
17,
11,
220,
16,
19,
11,
220,
16,
21
],
[
11,
220,
16,
17,
11,
220,
16,
19,
11,
220,
16,
21,
11
],
[
220,
16,
17,
11,
220,
16,
19,
11,
220,
16,
... |
I have a simple challenge for you this time. Given an array of positive integers A (or the equivalent in your language), replace each entry Ai with the sum of the next Ai elements of A, cycling back from the beginning if there are not enough items.
As usual, you can compete in any programming language and can take inpu... | [] |
The digital root (also repeated digital sum) of a positive integer is the (single digit) value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached.
For example, the digital... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
For the purposes of this question, a deck of cards is formatted in this way:
[
"AS", "2S", "3S", "4S", "5S", "6S", "7S", "8S", "9S", "10S", "JS", "QS", "KS",
"AD", "2D", "3D", "4D", "5D", "6D", "7D", "8D", "9D", "10D", "JD", "QD", "KD",
"AH", "2H", "3H", "4H", "5H", "6H", "7H", "8H", "9H", "10H", "JH", "QH", "K... | [
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
Background
In the game of Nim, players alternate removing "stones" from "piles": on each turn, a player must remove between one and all stones from a single pile. The object of Nim is to take the last stone or, in the misere variant, to force your opponent to do so -- however, it turns out the strategies are nearly id... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
Introduction:
Although I originally had a Dutch song in my head, where the lyrics are: "Doe 'n stapje naar voren, en 'n stapje terug" (which translated to "Take a little step forward, and a little step back"), when I searched for the full lyrics, I realized they only got back and forth, and never sideways.
So, instead ... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
],
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
],
[
220,
16,
11,
220,
17,
11,
220,
18,
11,
220... |
According to this question a Superb Shuffle™️ is defined as a full deck of cards (including jokers) which follows this set of rules:
No two cards (except Jokers) of the same suit are adjacent.
No card (except Jokers) is adjacent to one of the same value.
No card (except Jokers) is adjacent to one of an adjacent value ... | [
[
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20,
11
]
] |
Challenge
You are given three integers as input - min_value, max_value, sample_size, that you can pass to your answer as either array or several parameters.
Your task is to output a diagram in any convenient format, that shows the frequency of numbers in the (min_value, max_value) range showing up when a random number ... | [] |
Given a pattern (string or array format) of Bits :
[0,1,1,1,0,1,1,0,0,0,1,1,1,1,1,1]
The tasks is to replace any number of consecutive 1-Bits with an ascending number sequence starting at 1.
Input
Pattern (can be received as an string or array) Example:
String: 1001011010110101001
Array: [1, 0, 0, 1, 0, 1, 1, 0, 1,... | [] |
Introduction
In the not so distant future with the AI revolution, we will need a way to solve their captchas to prove we're not humans.
This challenge was inspired by CommitStrip.
Challenge
One such captcha is the challenge of calculating the sum of all odd digits of Pi from digit 1 to digit n, including the first digi... | [] |
I work at a bakery that serves Wheat, Rye, Barley, Grain, and French bread, but the baker's a little weird - he stacks the loaves in random order, and sometimes just leaves some shelves at the end empty.
Each day, the same customer comes in and asks for one of each loaf of bread, but the tricky thing is, he's a germoph... | [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
]
] |
A perfect square is an integer that is the square of an integer; in
other words, it is the product of some integer with itself.
Calculate the number of perfect squares below a number \$n\$ where \$n\$ will be taken as an input
Examples:
There are 9 perfect squares below 100: 1, 4, 9, 16, 25, 36, 49, 64, 81
Constrain... | [] |
Challenge:
Given a list of nonempty lists of integers, return a list of tuples of the following form: First list tuples starting with each element of the first list followed by the first element of every subsequent list, so the ith tuple should be [ith element of first list, first element of second list, ... , first el... | [] |
Description
OEIS sequence A096004 gives the
Number of convex triangular polyominoes [polyiamonds] containing n cells.
It begins:
1, 1, 1, 2, 1, 2, 2, 3, 2, 2, 2, 3, 2, 3, 3, 5
For example, a(8)=3 with the following three convex polyiamonds:
Input: 8
Output:
*---*---*---*---*
/ \ / \ / \ / \ /
*---*---*---*---*
... | [] |
Defintion
A centrosymmetric matrix is a square matrix that is symmetric about its center. More rigorously, a matrix \$A\$ of size \$n \times n\$ is centrosymmetric if, for any \$i,\: j \in ([1, n] \cap \mathbb{Z})\$ the following relation is satisfied:
$$A_{i,\:j}=A_{n+1-i,\:n+1-j}$$
Examples of such matrices
Here is a... | [] |
...or Toroidal Moore Neighbourhoods
Given positive integers h, w and a non-negative integer i, return all of the indices surrounding i.
You are to assume a matrix consisting of h rows of w elements, numbered from lowest, in the top left-hand corner, to highest, in the bottom right-hand corner, and return, in any reaso... | [] |
Challenge
Given nine numbers, a, b, c, d, e, f, g, h, i, as input which correspond to the square matrix:
$$\mathbf{M} = \begin{pmatrix}a& b& c\\ d& e& f\\ g& h& i\end{pmatrix}$$
Find the inverse of the matrix, \$\mathbf{M}^{-1}\$ and output its components.
Inverse Matrix
The inverse of a matrix 3 by 3 obeys the followi... | [] |
Challenge
Given a list of integers and a velocity, \$v\$, implement a sorting algorithm which simulates a program sorting the list from smallest to biggest at the given velocity.
Einstein's Theory of Special Relativity
What do I mean? Well assume your program takes a time, \$T\$, to sort a particular list. If you ran t... | [] |
This is a 2-dimensional version of this question.
Given a non-empty 2-dimensional array/matrix containing only non-negative integers:
$$ \begin{bmatrix}
{\color{Red}0} & {\color{Red}0} & {\color{Red}0} & {\color{Red}0} & {\color{Red}0} \\
{\color{Red}0} & {\color{Red}0} & 0 & 1 & 0 \\
{\color{Red}0} & {\color{Red}0} & ... | [] |
Motivation: Sometimes certain items in a list don't count towards your totals. For example, counting plane passengers in rows, where babies sit on a parent's laps.
Challenge: write a program to split a list of items into chunks. Each chunk (except possibly the last) is the same size, where size is defined as the number... | [] |
I'm trying to get the shortest way (character possible) to obtain List 3.
List 1 and List 2 are already given to me as arguments and are the same length.
l1 = [1, 2, 3, 4, 5]
l2 = ['a', 'b', 'c', 'd', 'e']
And List 3 should look like (yes, it needs to be a list):
l3 = ['a', 1, 'b', 2, 'c', 3, 'd', 4, 'e', 5]
| [
[
16,
11,
220,
17,
11,
220,
18,
11,
220,
19,
11,
220,
20
]
] |
Input
A non-empty binary matrix consisting of 3x3 sub-matrices put side by side.
Task
Your task is to identify valid dice patterns (as described below) among the 3x3 sub-matrices. Each valid pattern is worth the value of the corresponding dice. Invalid patterns are worth 0.
Output
The sum of the valid dice values.
Dice... | [] |
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